1. Field of the Invention
The present invention relates to fuel tanks having a check valve attached thereto, and more particularly, a check valve attached to a main body of a fuel tank.
2. Description of the Related Art
In a fuel tank of an automobile, a check valve is attached to a main body of the fuel tank in order to prevent liquid fuel and fuel vapors in the main body of the fuel tank from flowing back and being released to the outside during fueling. A conventional check valve has a rather complicated structure to attach the check valve to an inner wall of the main body of the fuel tank.
The object of the present invention is to provide a check valve having sufficient sealing properties with a simple structure as well as to provide a fuel tank with the check valve.
At least part of the above and the other related objects are attained by a first check valve that is attached to an inner wall of a main body of a fuel tank. The first check valve includes a casing having a fuel inlet and fuel outlet through which a supply of fuel is ejected from the valve casing to the main body; a valve disc for opening the fuel outlet only when sufficient fuel pressure is applied to the valve disc from the fuel inlet pipe; and, a fixation plate surrounding the casing and having an inner end and an outer end for hermetically sealing the main body. The inner end of the fixation plate is inserted through insert molding into an end of casing, and the outer end is arranged to be welded to the inner wall of the main body.
The first check valve of the present invention, which is attached to the inner wall of the main body, is set to the open position by a flow of fuel injected through the fuel inlet pipe, and accordingly, enables the flow of fuel to enter the main body. When no fuel is supplied, the valve disc of the check valve is kept in the closed position to close the fuel outlet of the casing, and thereby, prevent the liquid fuel and fuel vapors in the main body from flowing back and being released to the outside.
The check valve is attached to the inner wall of the main body via the fixation plate by welding. The fixation plate has an inner end inserted through insert molding into the main body. The fixation plate seals the main body from the fuel inlet pipe and the outside, thereby special sealing elements, such as O rings, are not required and reducing the total number of parts.
Having the fixation plate, which is inserted through insert molding into the end of casing, integrated with the casing simplifies the process of attaching the check valve to the main body.
In accordance with one preferred embodiment of the present invention, the flange of the casing has a ring-shaped seal projection that is protruded to surround the fuel outlet. The ring-shaped seal projection is pressed against and jammed to a side wall of the main body, thereby ensuring a seal of the main body from the fuel inlet pipe. This simple structure enhances the seal between the flange and the side wall of the main body.
It is preferable that the fixation plate has a handle, which is arranged on a circumference thereof to hold the check valve during attachment of the check valve to the main body. The hold facilitates the attachment of the check valve to the inner wall of the main body.
It is also preferable that the check valve include a spring that presses the valve disc to the closed position.
In accordance with another preferred embodiment of the present invention, the casing has a seat, and the valve disc includes a valve element that is seated on the seat in the closed position and removed from the seat in the open position to close and open the fuel outlet; an arm linked with the valve element; and an attachment that is connected with the arm and is formed to attach the valve disc to the casing. The valve element, the arm, and the attachment are integrally formed from a thin plate having elasticity. The arm is designed to press the valve element against the seat to cause the valve element to be seated on the seat in the closed position. The arm causes the valve element to be removed from the seat and thereby sets the valve element in the open position when the valve element receives a pressure of a flow of fuel applied thereto at a time of fueling.
The present invention is also directed to a first fuel tank including a main body, in which fuel is kept, and a fuel inlet pipe, which is connected to the main body and through which a supply of fuel is flown into the main body. The first fuel tank is provided with a check valve that is attached to an inner wall of the main body and is connected to a fuel conduit of the fuel inlet pipe. The check valve prevents liquid fuel and fuel vapors in the main body from flowing through the fuel inlet pipe and being released to outside. The check valve is opened by a flow of fuel in the fuel inlet pipe to allow the flow of fuel to be introduced into the main body. The check valve includes a valve chest connected to the fuel inlet pipe; a casing with a fuel outlet, through which a supply of fuel is ejected from the valve chest to the main body; a valve disc that is movable between an open position and a closed position, so as to open and close the fuel outlet; and a fixation plate that is formed to seal the main body from outside and fix the valve disc in the main body. The fixation plate has one end inserted in an end of the casing, which forms a flange, and the other end welded to the inner wall of the main body.
The arrangement of the first fuel tank facilitates the attachment of the first check valve to the fuel tank.
The present invention is further directed to a second check valve that is attached to an inner wall of a main body of a fuel tank, in which fuel is kept, and that is arranged in the vicinity of a fuel outlet of a fuel inlet pipe, through which a supply of fuel is ejected into the main body. The second check valve includes a fixation member that has a seat designed to surround the fuel outlet and is formed to fix the check valve to the inner wall of the fuel tank; and a valve plate that is attached to the fixation member and is movable between an open position and a closed position to open and close the fuel outlet. The valve plate includes a valve element that is seated on the seat in the closed position and removed from the seat in the open position, so as to close and open the fuel outlet; an arm linked with the valve element; and an attachment that is connected with the arm and is formed to attach the valve disc to the casing. The valve element, the arm, and the attachment are integrally formed from a thin plate having elasticity. The arm is designed to press the valve element against the seat to cause the valve element to be seated on the seat in the closed position. The arm causes the valve element to be removed from the seat and thereby sets the valve element in the open position when the valve element receives a pressure of a flow of fuel applied thereto at a time of fueling.
In the second check valve of the present invention, the valve plate attached to the fixation member is movable between the open position and the closed position in order to open and close the fuel outlet of the fuel inlet pipe. The valve plate is made of a thin plate having elasticity and includes the valve element, the arm, and the attachment, which are integrally formed. The valve plate is attached to the fixation member by means of the attachment, which is linked with the valve element via the arm. The arm functions as a spring that applies a pressing force in the direction of seating the valve element onto the seat. When the valve element receives a force of a flow of fluid applied thereto, the arm inclines the valve element to open the fuel outlet of the fuel inlet pipe. Since the arm presses the valve element against the seat, the check valve ensures a sufficient seal in the closed position.
The second check valve of the above configuration is not attached to the fuel inlet pipe, but is directly attached to the inner wall of the main body by the fixation member. This arrangement enables the check valve not to be tubular, but flat in shape, thereby simplifying the structure of the fixation member. The fixation member, which is formed to support the thin valve plate, needs a relatively thin wall thickness.
The second check valve includes the thin valve plate and does not require any spring to move the valve plate between the open position and the closed position or any mechanism for setting the spring. This arrangement simplifies the structure of the check valve.
In accordance with one preferred embodiment of the present invention, the valve element is formed in a disc shape, and the arm is arranged on a circumference of the valve element.
In accordance with another preferred embodiment of the present invention, the fixation member has a circular protection step, which surrounds a circumference of the seat and protrudes inward in the main body to protect the valve element. The circular protection step effectively prevents the elastic thin valve plate from being deformed during attachment of the check valve to the inner wall of the main body.
In one method for attaching the valve plate to the fixation member, the valve plate has a claw obtained by cutting and bending part of the attachment. The fixation member has an engagement recess, which receives the attachment of the valve plate inserted therein, and an engagement aperture, which is formed in the vicinity of the engagement recess. Insertion of the attachment into the engagement recess causes the claw to be fit in the engagement aperture so that the valve plate is attached to the fixation member.
In another method for attaching the valve plate to the fixation member, the attachment of the valve plate is welded and fixed to the fixation member.
In still another method for attaching the valve plate to the fixation member, the attachment has a lower extension bent to surround a circumference of the fixation member. In this application, the attachment is attached to the fixation member by the lower extension.
In accordance with still another preferred embodiment of the present invention, the fixation member has an attachment pawl, which engages with the inner wall of the main body to attach the fixation member to the main body, and a valve pawl, which engages with the attachment of the valve plate to attach the valve plate to the fixation member. This arrangement enables the fixation member to be attached to the main body without welding so that the main body may be made of a resin.
The present invention is also directed to a second fuel tank including a main body, in which fuel is kept, and a fuel inlet pipe, which is connected to the main body and through which a supply of fuel is flown into the main body. The second fuel tank is provided with a check valve that is attached to an inner wall of the main body and is connected to a fuel conduit of the fuel inlet pipe. The check valve prevents liquid fuel and fuel vapor in the main body from flowing through the fuel inlet pipe and being released to outside. The check valve is opened by a flow of fuel in the fuel inlet pipe to allow the flow of fuel to be introduced into the main body. The check valve includes a fixation member that has a seat designed to surround a fuel outlet of the fuel inlet pipe and is formed to fix the check valve to the inner wall of the fuel tank; and a valve plate that is attached to the fixation member and is movable between an open position and a closed position to open and close the fuel outlet. The valve plate has a valve element that is seated on the seat in the closed position and removed from the seat in the open position to close and open the fuel outlet; an arm linked with the valve element; and an attachment that is connected with the arm and is formed to attach the valve disc to the casing. The valve element, the arm, and the attachment are integrally formed from a thin plate having elasticity. The arm is designed to press the valve element against the seat to cause the valve element to be seated on the seat in the closed position. The arm causes the valve element to be removed from the seat and thereby sets the valve element in the open position when the valve element receives a pressure of the flow of fuel applied thereto during fueling.
The arrangement of the second fuel tank facilitates the attachment of the second check valve to the fuel tank.
These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with the accompanying drawings.